About the Logic Pro and MainStage sound library on Mac
After updating to Logic Pro 12 or MainStage 4 from earlier versions, your sound library is automatically cloned to a new, consolidated bundle file.
Starting in Logic Pro 12 and MainStage 4, all sound library files included with Logic Pro and MainStage such as software instrument patches, Apple Loops, and samples are stored in a single file called "Logic Pro Library.bundle." The new file streamlines sound library workflows like using your sound library on other computers and relocating your sound library to an external storage device.
How your sound library is cloned depends on where your current sound library is located.
If your sound library is on your Mac
When you first open Logic Pro 12 or MainStage 4, the app clones your sound library. The new file is located in your Music folder. The cloning operation requires no extra storage space. You don't have to delete the old sound library files to optimize storage space on your Mac. When you download new sound library content, it's stored in the new sound library file.
You can work on projects while Logic Pro or MainStage clones your sound library. If you close the app during the cloning process, the process resumes automatically when you reopen the app.
If your sound library is on an external storage device
If you moved your sound library to an external device, how Logic Pro or MainStage creates the new sound library file depends on whether or not your storage device is formatted as APFS.
The Apple File System (APFS) is the default file system used to format Apple devices and external storage devices.
Check the format of your external storage device
In the Finder, select the storage device in the sidebar
Choose File > Get Info. The format of the storage device appears in the General section.
Storage devices formatted as APFS
If you formatted your external storage device as APFS, Logic Pro or MainStage clones your sound library in the current location and requires no extra storage space. When you download new sound library content, it's stored in the new library file on the external storage device.
Storage devices formatted as Mac OS Extended or Windows-compatible file systems
If your sound library is located on an external device that's formatted as Mac OS Extended or as a Windows file system like MS-DOS (FAT) or ExFAT, Logic Pro or MainStage makes a copy of your sound library in the new file type. The storage device needs to have enough free space to accommodate both the older library items and the new library file.
If you have enough space on your storage device
After Logic Pro or MainStage has finished copying the library, you can delete the original sound library files to reclaim space on your storage device. If you also have older versions of the apps installed, don't delete the original sound library. The new sound library file isn't compatible with older versions of the apps.
If you don't have enough space on your storage device
An alert appears indicating that the storage device doesn't have enough free space for the new sound library file. To store the new sound library file on this storage device:
Note how much free space your storage device needs, then click OK in the alert.
Quit Logic Pro or MainStage.
To create space on your external storage device:
Delete items on the storage device then empty the Trash.
Move items from the storage device to another location like the desktop of your Mac.
Reopen Logic Pro or MainStage. Click Continue in the dialog about copying your sound library.
You can also do either of the following:
Get a new storage device and format it as APFS.
If you choose either of these options, you'll need to download the sounds you want then move the library to the storage device:
Open Logic Pro (or MainStage), then choose Logic Pro (or MainStage) > Sound Library.
Click Manage Packs in the Sound Library, then download the sound packs that you want.
Move the sound library to the reformatted or new storage device.